In Parker v. Gladden, the U.S. Supreme Court ruled that a bailiff's comments to jurors about the defendant's guilt violated the defendant's Sixth Amendment right to an impartial jury trial. The case involved Lloyd Eldon Parker Jr., who was convicted of armed robbery in Oregon state court and sentenced to life imprisonment due to prior convictions. During deliberations, one juror asked a bailiff what would happen if they couldn't reach a verdict; he responded by implying that another jury would find him guilty anyway because "he is as guilty as can be." Another time, he told two other jurors that there was no doubt about Parker’s guilt. These statements were reported after sentencing but before appeal proceedings began in earnest at state level courts which upheld his conviction despite these revelations citing harmless error doctrine among others reasons for doing so. The Supreme Court reversed this decision stating such conduct on part of court officials could influence jurors' decisions and thus infringe upon defendants’ constitutional rights even if it did not directly affect final outcome of their cases thereby setting important precedent regarding fair trials under American law system.

In the dissenting opinion for Parker v. Gladden, Justice Tom C. Clark argued that the majority's decision to overturn Parker's conviction based on a bailiff's comments to jurors was an overreach of federal authority into state court proceedings. He contended that there was no clear evidence showing that the bailiff’s remarks had influenced or prejudiced the jury against Parker, and thus it did not violate his constitutional rights under due process clause of Fourteenth Amendment as claimed by majority justices. Furthermore, he pointed out that Oregon courts had already addressed this issue appropriately and found no harm done in terms of fair trial standards being compromised. Therefore, according to him, intervention by Supreme Court was unnecessary and set a dangerous precedent for future cases where minor misconducts could lead to unwarranted retrials.